Polycarbonate copolymer

Abstract

A polycarbonate copolymer including a repeating unit represented by the following formula (1) and having a copolymerization molar ratio represented by Ar 2 /(Ar 1 +Ar 2 ) of 30 mol % or more and 47 mol % or less. In the formula (1), Ar 1 is a group represented by the following formula (2a) or (2b) and Ar 2 is a group represented by the following formula (3); and n is an average number of repetition and is 1.12 or more and 2.34 or less.

The invention claimed is: 
     
       1. A polycarbonate copolymer comprising a repeating unit represented by the following formula (1) and having a copolymerization molar ratio represented by Ar 2 /(Ar 1 +Ar 2 ) of 38 mol % or more and 47 mol % or less, 
       
         
           
           
               
               
           
         
         wherein in the formula (1), Ar 1  is a group represented by the following formula (2a) and Ar 2  is a group represented by the following formula (3); and n is an average number of repetition and is 1.12 or more and 2.34 or less; 
       
       
         
           
           
               
               
           
         
         wherein in the formula (2a), R 1  to R 3  are independently an alkyl group including 1 to 10 carbon atoms; and 
         in the formulas (2a) and (3), k is 1, m is 0, 1 is 0 and p is 2, and 
         wherein the chain end is a group represented by C(R) 3 —(CF 2 )n 35 -O—(CF 2 CF 2 O)n 34 -CF 2 CH 2 —O—, wherein n 34  is an integer of 1 to 3, n 35  is an integer of 1 to 5, and R is CF 3  or F. 
       
     
     
       2. The polycarbonate copolymer according to  claim 1 , wherein the chain end is a group represented by any of the following formulas: 
       
         
           
           
               
               
           
         
       
     
     
       3. The polycarbonate copolymer according to  claim 1 , wherein the reduction viscosity [ηsp/C] of a methylene chloride solution of the polycarbonate copolymer having a concentration of 0.5 g/dl at a temperature of 20° C. is 0.79 to 1.79 dl/g;
 the coefficient of viscosity of a tetrahydrofuran solution of the polycarbonate copolymer having a concentration of 10 wt % at a temperature of 20° C. is less than 500 cp; and 
 when the reduction viscosity is taken as X, the coefficient of viscosity is not more than a value (Y) calculated by the following equation:
     Y= 14.301× e   2.2781X ,
 
 
 wherein e is the base of natural logarithm (Napier's constant). 
 
     
     
       4. The polycarbonate copolymer according to  claim 1 , wherein the group represented by the formula (2a) is the following group: 
       
         
           
           
               
               
           
         
       
     
     
       5. A coating liquid comprising the polycarbonate copolymer according to  claim 1  and an organic solvent. 
     
     
       6. An electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive base, wherein the photosensitive layer comprises, as one component, the polycarbonate copolymer according to  claim 1 .